Multiple ionization of Argon by Helium ions

Abstract

We apply the continuum distorted-wave eikonal initial state and the independent electron model to describe the multiple ionization of Ar by He2+ and He+ in the energy range 0.1–10 Mev amu–1. Auger-like post collisional processes are included, which enhance the high energy multiple ionization cross sections via ionization of the inner shells. All Ar electrons (K, L and M-shells) have been included in these calculations. The results agree well with the experimental data at high energies, where the post-collisional ionization is the main contribution. At intermediate impact energies the description is also good though it tends to overestimate the triple and quadruple ionization data at intermediate energies. We analyze this by comparing the present results for He+2 in Ar, with previous ones for He+2 in Ne and Kr. It was found that the theoretical description improves from Ne to Ar and Kr, with the latter being nicely described even at intermediate energies. The present formalism is also tested for Ar inner shell and total ionization cross sections. In all the cases the results above 0.1 MeV amu–1 are quite reasonable, as compared with the experimental data available and with the ECPSSR values.